1. Field of the Invention
The present invention relates to a method and device for monitoring the level of particulate matter in a stream of hydrocarbons which are being produced from a well bore and, specifically, to a surface sand detection monitor for monitoring the type and amount of sand in a stream of hydrocarbons being produced at the well surface.
2. Description of the Prior Art
As oil and gas wells are being drilled through formations which generally are of an unconsolidated nature, the produced fluids can be expected to contain particulate matter, referred to herein as "sand." It is undesirable to produce particulate matter above a certain level with production fluids, because such production results in abrasion of the production tubing, valves and other equipment used to produce the well, as well as the equipment used to carry such fluids from the well. Unacceptable levels of sand in the production fluids can actually result in blockage of the production tubing, thereby halting fluid production altogether.
A variety of devices are known in the art for reducing the production of sand which involve "gravel packing" the well during completion operations. Gravel packing operations typically include the installation of a device on the production conduit or tubular work string which includes a slotted or ported cylindrically shaped member. This member is designed to prevent the passage of solid particles exceeding a predetermined size therethrough and into the interior of the production conduit. In a typical operation, gravel packing is introduced into an annular area between the production conduit or work string and the casing of the well or, in the event of a non-cased well, the well bore wall. The gravel used as the packing medium is deposited longitudinally along the exterior of the slotted or ported cylindrical member.
Gravel packing devices are shown, for example, in U.S. Pat. No. 4,856,591, issued Aug. 15, 1989, to Donovan et al. and U.S. Pat. No. 4,858,691, issued Aug. 22, 1989, to Ilfrey et al., both assigned to the assignee of the present invention.
Typically, after a well is completed, the flow of production fluids are routed through the production tubing in the well bore and through a surface conduit to a desired surface location which could be, for example, an oil and gas separator unit. The production flow rate is typically controlled by means of a "choke", or regulator, located in the surface conduit upstream of the oil and gas separator unit and other related surface equipment The choke includes an interchangeable orifice so that the flow rate of the produced fluids can be varied by interchanging orifices of different diameter. By properly selecting the flow rate of the produced fluids, sanding problems can be greatly reduced or eliminated.
It is an object of the present invention to provide a surface sand detection monitor in the surface conduit to provide information regarding the type and amount of sand being produced with the production fluids. Using this information, the flow rate of the produced fluids can be adjusted by adjusting the production flow regulator, as required, to minimize sand production.
It is also an object of the invention to provide a method of monitoring the level of sand in a stream of hydrocarbons which are being produced from a well bore in order to provide an indication of the appropriate time for installing or activating gravel packing devices and methods to prevent problems caused by excess sand in the produced fluids.
Another object of the invention is to provide such a surface sand detection monitor which can be utilized to provide information regarding the type and amount of sand in the produced fluids without requiring that the well be shut-in at any point in the information gathering process.